CLOK: a chemigenetic multicolor labeling system to visualize neuronal birthdate and circuit integration.

CLOK enables precise multicolor labeling of neurons by birthdate, revealing distinct maturation trajectories in zebrafish visual and motor systems.

• Why it matters: Understanding neuronal integration and circuit development is crucial for decoding brain plasticity, but current methods lack high throughput and resolution.
• What they did: The study developed CLOK, an in vivo birthdate-labeling system using HaloTag technology with fluorescent ligands, coupled with optical tools for calcium, voltage imaging, and optogenetics in zebrafish.
• The result: CLOK allows detailed tracking of neuronal maturation and circuit integration, facilitating optical interrogation in a living, developing vertebrate, advancing studies of brain development and plasticity.